The present invention relates to a manufacturing method of organic modifier-free exfoliated nano clay-polymer composite. The manufacturing method of organic modifier-free exfoliated nano clay-polymer composite includes (S1) dispersing layered clay nanoparticles and dissolving a thermoplastic polymer in an acidic solvent; (S2) adding the product of step (S1) to a polymer non-solvent incapable of dissolving the polymer, but capable of dissolving the organic modifier separated from the organized layered clay nanoparticles; and (S3) separating an organic modifier-free exfoliated nano clay-polymer composite from the product of step (S2). The inventive manufacturing method can maximally improve the physical properties of composites through the addition of the exfoliated clay nanoparticles by removing the organic modifier that may deteriorate physical properties of the composite from the exfoliated clay nanoparticles dispersed therein.